1. Technical Field
This invention relates generally to systems and methods for inspecting the interior of a container, and more particularly to a system and related methodology for mapping information about the interior of a metal cargo container that can be used to produce an image representing container contents.
2. Background Information
Metal cargo containers appear in various forms, such as semi-trucks, box cars, and the large metal shipping containers used worldwide on ships and railroad flat cars. They enjoy widespread use for holding and protecting various types of legitimate goods during shipment. But illegal items ranging from stolen cars and weapons to drugs also find their way into some metal cargo containers and so inspecting personnel need effective means for conveniently examining cargo container contents.
Existing scanning systems do not readily adapt to the task. Those used at airports to scan baggage are far too small for large cargo containers. In addition, adapting existing X-ray scanners and the like to large, metal cargo containers introduces other problems, such as the need for significant power and the potential hazards of X rays. Furthermore, metal cargo container walls can defeat systems attempting to pass ultrasonic or rf energy through the container. Thus, inspecting personnel need a scanning system that overcomes those drawbacks. In addition, the system should be sufficiently portable to enable use at locations where metal cargo containers may be found while being conveniently installable at existing inspection stations.